Let be the circle of radius centered at the origin , and . The radian measure of an angle at the center of is the length of the arc it cuts on . Since the full circle has circumference :
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Mathematics · 术语表
书籍暂未推出简体中文版——当前显示英文版。
Mathematics · 术语表
Let be the circle of radius centered at the origin , and . The radian measure of an angle at the center of is the length of the arc it cuts on . Since the full circle has circumference :